This invention relates generally to an apparatus for placing solder rings around terminal posts for subsequent soldering to a printed circuit board, for example, and more particularly, it relates to an apparatus for cold crimping successive portions of a continuous strip of solder into rings of doughnuts around a plurality of terminal posts which are supported in parallel relationship upon a common carrier strip.
One well known way of securing terminal posts through holes provided therefor in printed circuit boards is to place a doughnut-shaped ring of solder around the terminal post which is then, or has previously been, inserted in a hole provided therefore in a substrate, such as a printed circuit board. The board is usually positioned such that the solder doughnuts rest against the board and usually against a conductive pad or area formed on the board. Heat is then applied to melt the solder rings, thereby securing the posts to the board and making electrical contact between the posts and the conductive surfaces on the board. The placing of the solder rings upon the terminal posts has been done a number of ways, including a manual operation whereby a human operator places the solder rings individually on the posts after or before the posts have been inserted into a printed circuit board.
An improved method and apparatus for applying solder rings to terminal posts which are connected in parallel arrangement to a common carrier strip is disclosed in co-pending application Ser. No. 466,322 filed May 2, 1974, by Robert F. Cobaugh and James R. Coller, entitled "Method and Apparatus For Prescrimping Solder Rings On Electrical Terminal Posts", now Pat. No. 3,886,650, and incorporated herein by reference.
In the afore-mentioned application the terminal posts are first passed through an oven in which they are heated. Subsequently, the heated terminal posts and also a strip of solder having a substantially rectangular cross-sectional configuration are passed together through a first pair of rollers whose perimeters are tangential and configured so that the heated terminal posts are caused to be pressed against one edge of the strip of solder. The heated posts melt their way into the solder strip until the posts are approximately half-way through said solder strip. The posts, with the solder strip now attached thereto, is passed through a second pair of rollers whose perimeters are tangential and configured so that the solder strip is crimped or pinched at its edges, i.e., in a direction parallel with the major surfaces of said solder strip, in-between adjacent terminal posts to cold work the solder strip into semi-completed rings around each terminal post. The pinching or crimping of the solder strip is almost sufficient to completely break the strip of solder. Thus, the resultant product is the row of terminal posts still retained on the carrier strip at one end and having the semi-complete solder rings formed around each terminal post with each of said semi-complete solder rings joined to the adjacent solder rings by a thin, neck-like element of solder.
While the foregoing method and apparatus performs very well and is employed commercially, it would mark improvement in the art to provide a simplified apparatus requiring less structure and which does not require heating of the terminal posts.